The present invention relates to a drawing machine, also known as plotters, and more particularly to a raster type plotter, in which the drawing is produced by the combined movements of the printer head transversal to the paper advancement and the ink distribution from the different pens on the printing heads (or pins on an inked tape) at the appropriate positions.
The machine forming of this invention is especially useful for the tailoring industry, or another with similar characteristics as to the type of pieces used, precision required, density of lines per unit of surface drawn, etc., that also makes it necessary to reduce the cost of the drawing media, as great amounts of this are consumed.
The drawing plotter is well known in the prior art as a machine that performs a graphic representation of design in different industrial fields, such as engineering, cartography, garments, furniture, etc.
There are two types of drawing plotters according to the type of paper used for the drawings: those that use paper cut to the size of the drawing to be made, or those using roll paper. The former tend to be limited by usually handling standard paper sizes up to one meter long, or require tables as large as the area of the drawing to be made, with the consequent high price of the machine obtained. The latter perform the drawing by combined movement of the paper and the drawing tool although they require very precise control of the bi-directional movement of the paper.
The types of machine aforementioned are known as flat bed plotters and drum plotters, the technology of which is well known, as may be seen in patents U.S. Pat. No. 3,857,525 (Gerber) by the firm Gerber Scientific, or the Spanish Patent No. 509082 by Investrxc3x3nica, or the U.S. Pat. No. 4.593.469 by Autographic Business Form Inc.
To solve the inherent problems of these and others, other types of plotters were developed, to perform the drawing on tables that are smaller sized than the drawing to be performed; the full operation was performed on successive zones, then moving the paper across the drawing area, once the whole operation was performed in the work zone, moving the paper already drawn to a storage area and providing a new area of paper in the work zone. This required precise joints, although few of them. Examples of this technique may be seen in the patents U.S. Pat. Nos. 4,091,980 and 4,916,819.
In any case, the performance of such machines in meters of paper drawn per unit of time is very much dependent on the density of the drawing; moreover, due to the precision required, the mass in movement must be as little as possible.
The disadvantages of this type of machine avoided by raster type plotters, where the drawing is performed by the combined action of the movements of the printer head and advancement of the paper in a stepped manner. This is the case of the patent U.S. Pat. No. 4,686,540.
The performance by such machines is closely related to the width of the zone swept. On the other hand, the drawing is usually made on the perimeter of a cylindrical surface, on which the distance from the printer head to the paper is not constant, this leading to low yield and drawing qualities, limited sweep widths and the problems of excessive paper advancement.
To solve this problem, the previous patent uses several heads spaced out one from the other in the direction of the movement of the set of these, so when their displacement length is reduced, productiveness increases. This solution has the disadvantage of the head bearing table and a decrease in quality due to the excessive number of joints.
Therefore, there is a need to develop a drawing plotter which provides drawings of high quality and yield, and which is also compact.
The object of the present invention is to provide a flat raster plotter controlled automatically by a controller located under the control panel.
In accordance with the preferred embodiment of this invention, the machine consists of drawing instruments carried by a carriage that travels on rails in direction X on the drawing plane, and that carriage is mounted on another carriage that travels in direction Y perpendicular to the movement of the previous carriage, so the printing head bearing carriage may move to any point on the plan.
The relevant movements in both directions X and Y are produced by the movement generated by the motors, one controlling each displacement. The movement of these motors is transmitted directly from their axles to the respective drive pulleys by belts connected to the respective carriages.
The printing heads, of the linear group type, are mounted on the above heads so the total sweep width is the number of times the linear group as the number of heads used, producing the drawing by passing successively over the surface to draw, located on a flat table with a much greater width than the relevant size of the linear group of heads.